(CNN) –– More women over 35 are giving birth for the first time, according to a government study released Friday. The report, issued by the National Center for Health Statistics at the Centers for Disease Control and Prevention, looked at data compiled over the past four decades.
Among the findings:
- In 2012, there were more than nine times as many first births to women over age 35 than in the 1970s
- From 2000 to 2012, first birth rates rose 35% for women aged 40 to 44, and 24% for women aged 35 to 39
- The first birth rate for women aged 40–44 has more than doubled since 1990
- In the past 20 years, first birth rates rose for older women across all races. The largest increases were seen for non-Hispanic white and black women, and Asian or Pacific Islander women
The study also looked at first birth rates state-by-state. Researchers found only Mississippi, Oklahoma, Arizona and Idaho had no significant birth rate change for older women.
The study authors point out that there are pros and cons for women waiting to have children. Older moms typically have more resources, including higher incomes and better education than younger first-time moms. But women who have their first children after 35 are more likely to have health problems, as are their children.
According to the Southern California Center for Reproductive Medicine, a woman in her 20s has a 20 to 25% chance of conceiving naturally every time she menstruates. At that age, the rate of miscarriage is anywhere from 5 to 10%. By 34, the likelihood of a woman conceiving naturally drops to 15%, and the miscarriage rate is 20%. Women over 45 have a 1% chance of conception, and are five times as likely to miscarry as women in their 20s.
You can read the complete study on the CDC website.